The crew of the shuttle Atlantis, capping a cliffhanger countdown, thundered triumphantly into space Friday on a weather-delayed flight to put a spy satellite in orbit over the Soviet Union.

With veteran shuttle skipper Robert "Hoot" Gibson and co-pilot Guy Gardner at the controls, Atlantis' three main engines flashed to life at 7:31 a.m. MST - just one minute before the end of the ship's "launch window." The countdown was in doubt to the last instant because of worries about the weather.But the shuttle's 14-story redesigned solid-fuel boosters ignited with a flash 6.6 seconds after main engine ignition and Atlantis majestically climbed away from Launch Pad 39B, leaving a churning cloud of dirty brown exhaust in its wake.

"Ignition and liftoff!" said NASA spokesman Hugh Harris as the shuttle thundered skyward. "Atlantis begins another space voyage!"

As the orbiter cleared its launch gantry, the nozzles at the base of each booster swiveled on computer command, rolling the ship about its vertical axis and placing it on a trajectory that will allow its presumed $500 million spy satellite payload to fly over 80 percent of the Soviet Union.

The astronauts made the climb to orbit in public silence because of Air Force security restrictions that forced NASA to treat the flight as a top-secret mission. Only the voice of Brian Welch, a mission control commentator, was released to the public after Atlantis cleared its gantry.

Top NASA officials hailed the launching as a "good Christmas present" from a "truly professional launch team." Said NASA Administrator James Fletcher: "This is probably the best performing real-time team ever. I don't know how you could do better. You are just a super team!"

The goal of the classified flight reportedly is to place a high-technology radar reconnaissance satellite code-named Lacrosse in orbit that sources said was capable of taking detailed images of targets on the ground at night and through cloud cover.

In any case, Atlantis was declared safely in orbit about an hour after the 81/2-minute climb to space and the ship's five-man all-military crew _ Gibson, Gardner, Richard "Mike" Mullane, Jerry Ross and William Shepherd _ presumably settled down to opening the shuttle's payload bay doors and beginning initial checkout of the secret payload.

"You have made a contribution to the nation's national security," Air Force Secretary Edward "Pete" Aldridge told NASA. "Thanks for a great job."

Because the mission was stamped top secret by the Pentagon, NASA was prevented from releasing details about the flight, including any information about the hush-hush payload or when it will be deployed.

"The vehicle is in very clean shape," Welch said. "There are no systems problems whatever to report. The assent of Atlantis was very clean, by the numbers, normal in every respect. They had a successful insertion into low Earth orbit."

The duration of the 27th shuttle mission, the second since the Challenger disaster, was classified, although the flight could end as early as Monday with a landing at Edwards Air Force Base, Calif.

Blastoff came with only nine minutes' warning when NASA managers determined weather conditions were safe enough for launch. The countdown stopped briefly atthe T-minus 31-second mark because of apparent problems with weather at an emergency landing site near Zaragoza, Spain, but it quickly resumed.

The launch came a day behind schedule because of high-altitude wind shear that forced NASA to delay the countdown Thursday.